Estradiol 17b (E) acts centrally to influence both reproduction and behaviors in mammals, and the neuropeptide oxytocin (OT) is important in coordination of ovulation with mating behaviors. Two areas of the brain, medial preoptic area (MPOA) and medial basal hypothalamus (MBH), have important roles in this coordination. Dr. Caldwell has observed that E conjugated at position 6 to bovine serum albumen (E-6-BSA) stimulated OT release from anuclear homogenates of the MPOA and MBH. The present studies will examine whether E-6-BSA stimulates OT release by acting on a membrane/cytoplasmic E receptor or on a novel receptor for sex hormone binding globulin. Both undergraduate and graduate students will participate in the research.